Pneumatic drill.



M. HARDSOGG.

PNEUMATIG DRILL. APPLICATION FILED APB.. 18

Patented Sept. 29, 1908.

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Y M. HARDSOGG.

PNEUMATIGl DRILL. APPLIGATIO'N FILED APR. 18,1907.

I Patented sept. 29, 1908.

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M. HARDSOCG.

PNEUIMIATIG DRILL. APPLIGATION 'FILED AP3.1B,19Q7.

Patented sept. 29,' 190s.

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Win eges; @www MARTIN HARDSOCGMOF OTTUMWA, IOWA.

'V PNEnMATrc :DRILil Specification of Letters Patent.

A Patented Septv29, 1908.

Application 'filed April 18, 1907. Serial No. 368,885. t

To all 'whom 'it may concern:

Be it known that I, MARTIN HARDsooG, a

` citizen of the United States, residing at Ot` tumwa, in the coui1ty of Wapello and State of Iowa, have invented certain new and use.-l

ful Improvements in Pneumatic Drills', ofv

which thel following isa specification.

This invention relates to pneumaticdrills more especiall desi ned-for V,cutti lar e;

Y ng g openings, and particu arly adapted for use in f tunneling or making lateral cuttings in minstruct ahead carrying a ing and rock drilling,

and other similar operations. f

The objects of the invention areto construct a drill having .a plurality of cutters or bits, each cutter' or bit independently operative, and all the cutterslor bits simultaneously operative; to construct a casing havin y aI closing head with a-cha`mber and radia passages leading therefrom, eachradial passage connected with a longitudinal passage inthe casing'forsupplyingair, or other medium under pressure, to each passage; to conlurality of .neumatic hammers aid a pliirality of iven stems, each stem having connected there# with a tool head with bits or cutters; to furnish a plurality of casings loca-ted in a carryl ing head, each casing having a central 'chamf ber to receive a driving hammer anda driven steni,' and each casing having an induction passage for admitting fluid `to drive the hami mer and an eduction passagefor exhausting .fluid from in front of the drivingend of the .f hammer; to furnish a plurality of drills, each drill operated bya driven hammer, with the drills arranged in a circle and coperating with a central drill operated by a driven hammer; to construct a main shell or casing h' ving a plurality of longitudinal passages and a carrying casing or head having a plurality of passages coinciding with the Klongitudinal passagesof the main Sheller casing and sup'-V plying compressed air, or other medium under pressure--to a plurality of barrels arranged in a circle, and each barrel havin a chamber to receive a driving hammer an a driven stein; to construct a pneumatic drill having a plurality of tool heads, each carrying bits or cutters and arran ed in a circle, and having also a-central tooFhead carrying bits or cutters, with allthe tool heads operated by pneumatic hammers; and to-improve generally the construction, arrangement and operation ofthe pluralityv of pneumatic drills ing, and the ycasing A row; Fig. 12

, .rying tube 1, from which cham inafterdescribed d claimed.

In the drawing A igure 1 is a sectional elevation 'of the complete drill, taken through utwo of the outer drills-and the central drill;

Fig.' 2 asimilar view to Fig. 1', taken on a line passing between two outer drills and through thel central drill; Fig. 3 a s ide elevation of the complete drill of the invention; Fig. 4 an end .elevation of the drill .of the invention, showing thetool head with the bits or"cut ters; Fig. 5 a face view on the dividing line between the main Sheller casing andthe casing or head carrying the drills; Fig. 6 a cross section on line a-a of Fig.. 1; Fig. 7 a cross section on line b-b of Fig. 2; Fig. 8 a cross section on liiie c-c of Fig. 1; Fig. 9 a cross section on line d-d of Fig, 1; Fig. 10 an enlargedlsection in-detail, showing two of the drills and a portion of the main shell or casdrills, with the supply and discharge passages for compressed air, or other medium under pressure; Fig. 11 a cross section on line e-*e of Fig. 10,looking in the direction of the ara cr'oss section on line f-f of Fig. 10, looking in the direction of the arrow; and F ig. 13 a detail, partly in'section, of the or head carrying thev Y* lower end ofI the central barrel and its tool head. l

The construction shown has a supply pipe 1 for compressed air, or other medium under pressure, with an encircling flange 2 forming a conveyer'or flight for removing the cuttings, dust-and fine particles produced in the operation of `the drill. The forward end of the supply and carrying tube 1 is threaded into a neck or wall 3 on a closin head 4, and

the closing head 4 has a centra chamber 5 in line with'the interior ofthe supply and car- C er 5 radial passages 6 lead outwardly, each passage terminating in a port 7 downwardly opening through the inner face of the head, as shown in Figs. 2 and 7. Each port 7 communicates with and is in line with alongitudinal passage 8, formed a main shell or casing 9 constituting the rear section `of the frame, and the v head 4 and main shell orcasing 9 are connected with a casing or head 11, constituting the front section of tl'e frame, by tie rods 10, passing through the head 4 and the main shell or casing 9and threaded into the inner end of the head or `casing 11, as shown in Fig. 2. The exterior face of the head 4, the main shell or casing 9 and the head or casing 11,

` have a plurality of grooves 12, and the mteriorface of the head 4, the main shell or casing 9, and the casing or head 11, have grooves y 13, as shown in Figs. 3, 4 and 5. The exterior grooves or passages 12 are for withdrawing the cuttings, dust and ine particles from in front of the bits or cutters, and the interior grooves or passages, allow dust and fine particles to escape from the interior of the pneumatic drill, as a whole, to be discharged 15 around the exterior of the drill.

' A central tube 14 is, at its outer end,`

threaded int-o the head, 4, so as to be in communication with the chamber 5, and the inner end of this tube 14 is threaded into the l. 2 0 end head of a barrel 15, and the barrel 15 has,

*on opposite sides, longitudinal passages 16, each'passage terminating at its outer or rear end in a radial or laterally extending port 17, 7each. port in communication with a cross y passage or chamber 1S at the end' of the supply tube 14, so as to admit fluid into the side or longitudinal passages 16, for operating or driving the hammer in the chamber ,of the barrel. V y, Each passage or chamber 18, asshown, is formed between the end ofthe sup ly pipe or tube 14, and a closin head or piilg 19, -for the rear end of the ciamber of the barrel. Each side or longitudinal passage 16, at its inner or forward end, terminates in a radial or laterally extending port 20, and each port 20 is in communication with a chamber 21 f formed in the Wall of the barrel 15, so as to admit iiuid into the chamber 21 for receding the hammer. The chamber of the barrel has a circumferential wall 22, located between the chamber 21 and a chamber 23, and the chamber 23 is continuedl as a chamber or hole 24 into which is threaded the body of the plug` 19, so as to eectually close the rear end of the chamber of the barrel, as shown in Fig. 2. The interior ofthe chamber of^the barrel has a circumferential wall 25, located between the chamber 21 and a chamber 26, and the wall 25 furnishes a guide and support for the body 27 of a pneumatic hammer, having a striking end at the front and an enlargement or head 28 at the rear; and the enlargement or head 28 furnishes an abutment-or end face 29 against which fluid acts to recede the hammer into a striking position. The hammer has a central longitudinal hole 30 opening through the end of the enlargement or head ,28, and adjacent to the rear end of the passage 30 are lateral passages 31 leading through the enlargement or 1' head; and at the front end of the longitudinal assage 30 are lateral' orts or assages 32 eading thrpugh the bo y of the ammer. A port 33 leads from opposite sides of the chamber 26, and each port 33 is in conmumication with a side or longitudinal passage 34, leading to the front end of the. barrel of the hammer. Each side or longitudinal passage 34 is in communication with a tube 35, and each tube 35 enters a hole or passage 36 in a tool head 3T, which tool head is carried by a shank or stem 38, forming the driven shank or stem operated upon the hammer. The cross or tool head 3T carries, in the construction shown, a plurality of bits or cuttels 39, for performing the cutting or drilling operation by which a central hole is made in the material being operated.

The compressed air, or other medium under pressure, iiovvs through the supply tube 14 into the cross passage 18, and through the ports 17 enters the side or longitudinal passages 16, to discharge at the ports 20into the chamber 21, for the compressed, air, or other medium under pressure, to act on the abutment or end face 29 of' the enlargement or head 2S, and recede the hammer to its striking or driving position. The hammer is receded a suficient distance for the lateral passages or ports 36 to pass the rear end of the wall 22, for compressed air, or other medium under pressure, to ente-r the chamber 23 and flow into the central passage 30 of the hammer,'and act against the front end of the .passage and rear end of the hammer, and

cause the hammer to deliver the blow; and when in the receded position, the ports or passages -32 are closed bythe entry of such ports or plassages within the wall 25, preventing t e escape of compressed air, or other medium under pressure, through the passages or ports 32, until the hammer has deliveredl its blow. The forward thrust or drive of the hammer carries the ports or passages 31 within the inclosing Wall 22, closmg such ports or passages, 'and carries fthe ports or assages 32 into communication with the c amber 26, for the compressed air, or other medium under pressure, to escape from the passage 30 into the chamber 2G, and flow through the ports 33 into the passages 34, and discharge through the tubes and passages or holes`36, in the. front of the cross or tool head 37, and act to carry away the cuttings, dust and fine particles from the. bits or cutters, giving a perfect clearance, after each blow of the hammer, for thc next succeeding operation of the bits or cutters.

The central drill, by its bits or cutters, makes a hole, central of the core, cut. out by the bits or cutters of the drill, so that, if desired, a dynamite cartridge, or other explosive, can be entered into the central hole for breaking up the core, so as to permit of the.

easy removal of the broken mass; and, as shown, the lcentral drill acts slightly in advance of the outer drills in doing its work, which is desirable, as the barrel, with its drill, furnishes a center pin or bearing for the ,f sure.

revolving or turnin of the drill, as a whole, in the operation of t e drill.

The casinor or head 11 has, in its inner end face, a plurality of holes or passages coinciding with and in communicationwith the holes'or passages 8 in the main shell or casing; and, as shown, the passages 8 are nearer the inner face than the outer face of. the shell or caslng 8, and the holes or passages 40 start from the vend of the passages or holes 8 and have a slight outward inclination, Jso as to terminate at their inner ends at a central point between the inner and outer faces of the head or casing 11, as shown in Fig. 2. The passage 40 communicates with a cross passage 41,formed in t-he body of the head or shell 11, as shown in Fig. 10 and at each end of each passage 41 is a circumferential passage 42, into which the passage 41 discharges compressed air, or other medium under pres- The head or shell 11 has entered thereinto a plurality of hammer barrels 43, the number of hammer barrels varyin with the size of the head or shell, but enoug hammer barrels being provided to entirely fill the end of the head or shell, as clearly shown in Fig. Each barrel 43y has, on opposite sides, lateral ports or assages 44 communicating with the circumflerential passages 42 around each barrel, and eachport or passage 44, at its inner end-communicates with a chamber 45 formed Within .the interior of the barrel. A circumferential wall 46 is formed on the inner face of the wall, and'is located betweenthe chamber 45 and a chamber 47, .which chamber is continued as a chamber or hole 48 to receive a closing plug-49, by means of which the chamber of the hammer barrel is tightly closed at its rear end, as shown in Fig. 10. A circumferential wall 50, on the inner face of the barrel, is located between the chamber 45 and a chamber 51, and the.

circumferential wall 50 furnishes a guide and bearing for the body of the hammer 52, having a front or striking end with an enlargement or head 53 at its rear end, furnishing a shoulder or abutment ,54 for fluid to adt and recede the hammer to striking position. The body of the hammer has a central longitudinal passage 55 extending through the enlargement or head 53; and adjacent to the rear end of'the passage 55 are lateral ports or `passages 56, extending through the enl'ar e- -ment or head; and at the front end of t e passage 55 are lateral por-its' or passages 57,

which are brought into communication with the chamber 51, when the hammer has com- A pleted its strike or blow, as shown in Fig. 10.

he chamber 51, on opposite sides, has lateral ports'58 communicatin with a circumferential passage 59, formed in the vbody of the head or shell 1 1 around each hammer barrel 43, and each'circumferential'passa e 59 communicates with a cross passage-60, eading from which isa longitudinal passage 61 gulde and bearmg in cross diameter, with 6, to discharge at eachport 7 into t terminating at the end ofthe head or shell 11, so yas to discharge compressed air, or other medium under pressure, in front of the head or shell.

Each hammer barrel has, at its front end, an inner circumferential wall 62, forming a which is retained in the chamber therefor of the barrel by meansof a slot 64 in the shank or stem, and a barl or key, secured in the `wall of the barrel and passing through the slot, as shown in Fig. 10, so as to hold the shank against dropping out and at the same time permitting of the necessary end movement for the operation of the cross head with the drill bits or cutters. The shank or stem 63 extends from a cross or tool head 66, carrying drill bits or cutters 67 of, a suitable formation to operate and drill or cut a hole, and the arrangement of and the length of the cross head with the bits or cutters is such as to cause each tool to'make a hole of greater diameter than the thickness of the wall or shell 11 as shown in Fig. 4; and the drill headsare spaced apart a suflicient distance, so as to have a clearance between the heads and the bits or putters, by which `a hole or circular channel is cut of a greater diameter than the diameter of the a central core inside of the main shell or casing and the head or .casing carrying the hammer barrels, such core having a central hole, cut by the central drill orptool as already described.

The operation for all ofthe outer bits or cutters is the same, so that a general description will answer for each outer pneumatic hammer with its tool head and bits br cutters. VThe supply and carrying pipe 1 delivers compressed air, or other medium under pressure, tothe chamber 5, and the com- 'ressed air, or other medium -under pressure, ows through-the plurality of radial assages e companion longitudinal or'side passage 8 in the main shell or casing 9; and from the passages 8 the compressed air, or other medium under pressure, enters the passages 40 in thehead or shell for the barre hammers, to flow into the cross passages 41 from the several passages 40 and enter the circumferential passage or chamber 42 of each hammer'barrel. The compressed air, or other medium under `ressure, supplied to' the chamber 45 by the ateral ports 44 from the circumferential chamber or passage 42, acts against the abutfor a shank or stem 63,

main shell or casing ment or end face 54, and recedes or forces air, or other medium under pressure, enters the passage 55 throught-he lateralports 56,

and when the ports 56 are opened to admit .fluid the ports 57 are closed, against the escape or eduction of fluid, by the withdrawal of the ports 57 within the circumferential wall 50, so that the fluid can act fully to cause the hammer to strike the blow. The ports or passages 56 are closed, when the hammer is advanced by the ports entering the circumferential wall 46, and with the delivery of the blow-by the hammer `the lateralv ports or passages 57 open into the chamber I 51, allowlng compressed air, or other medium under pressure, to escape into the chamber 51 and flow out therefrom, through 'the lateral ports or passages 58, into the circumferential passage 59 to enter the cross passage "60 and discharge through the long1tudinal passage 61, in front of the head or shell carrying the pneumatic hammers and the tool. The forward thrust or drive of the hammer 52 advances the driven shank' or stem 63 to the limit of the slot 64, advancing the cross head 66, and causing the bits or cutters of the drill to act on the material being o erated upon, and the blow or strike of the plilrality of youter hammers will be simultaneous, givf ing a-simultaneous advance andcutting operation for the pluralityT of bits or cutters.

l The arrangement shown has an induction passage for admitting compressed air, or other medium under pressure, to operate the hammer between two adjoining hammer barrels, and the cross passage 41 for each. induction passage is common to the two adjoining hammer barrels, and this is also true lof the induction passages, each cross eduction passage being common to two adjacent hammer barrels, and each longitudinal eductionpassage being located between two adjoining hammer barrels, so that the educted, compressed air, or other medium under pressure, will discharge between the two adjoining bits or cutters. The construction shown has twelve hammer barrels,-each with a drill bit or cutter, but a greater or less number could be used, the number varying according to the diameter of the head or shell.

It will be understood that in arranging thel bits or cutters, in a circle around a common center, that the cutting of each drill shall be greater than the thickness of the wall of the head or shell, so as to have the plurality of drills act and cut a circular channel, leavinga central core which can be .broken up and destroyed or removed, after withdrawing the drill, as a whole, from the cutting or tunne made by thedrill. The compressed air, or other medium under pressure, discharged in front of the drill, will force the cuttings, dust and fine particles around' the periphery of the drill, and the cuttings), dust and fine particles will be forced rearward, in the s ace between the shell or casing and the will of the hole cut, by the force of the compressed air, or other medium under pressure, which escapes around the periphery of the main shell or casing, and the cuttings, dust and fine particles, forced rearwardly and held, in passing, by the grooves on the ,exterior of the main shell or casing, will be caught, by the conveyer or spiral encircling the supply and carrying tube, and bc conduct/ed rearwardly'and discharged at the end of the supply and carrying tube, or otherwise, as may be desired.

The main shell or', casing 9, with the head or shell 11, constitute a frame for the drill,

which frame has therein passages for inducting fluid to a plurality of animer barrels and passages for educting fluid from a lurality of hammer barrels. The frame wit the induction passages for compressed air, or other medium under pressure, furnishes a means for supplying compressed air, or other medium under pressure to operate a plurality of hammers, and after operating the hammers, the compressed air or other medium under pressure, is discharged so as to serve as the means for removing, from the cutting or forward end of the drill, the cuttings, dust and fine particles that would interfere with the operation of the drill, and the discharge of'the air, or other medium under pressure, from each of the barrels, leaves a perfect clearance for the acting or forward end of the hammer against back pressure, from the compressed air, or other medium under pressure, that would interfere with the blow struck by Athe hammer.

The compressed air, or other medium under pressure, ldischarged in advance of the forward end of the frame, in connection with the spiral flange ofthe supporting tube, fur- -nishes a means by which the cuttings, dust and fine particles will be carried away from the acting end of the drill or other tool as fast as produced, and. so as to prevent the cuttings, dust and fine particles from interfering with the operation of thebits or cutters.

The frame of the resent invention, with its central drill, and) its plurality of outer drills, arranged in a circle makes a drill which is especially adapted for use in mak- ,g

ing channels or cuts having a large diameter, the diameter of`the channel or cut varying with the diameter of the drill, and with the drill of the present invention, having a plurality of outer bits or cutters arranged 1n a circle, a hole or tunnel of a suflicient size in cross section to admit the body of a workman or operator, or even larger, can.be made without any trouble or inconvenience, as the outer circle of bits or cutters wlloperate to cut a circular channel, leaving a central core, and this core can be ierced, by the central lbit or cutter so as to orm a hole for placing rality of pneumatic hammer barrels, can be is shown for use in connection with a;v plural-v ity of pneumatic hammers, and with a plu-Y removed from the rear section `or main caslng or shell of the frame, when necessary, for repamng any hammer barrel, or hammer, or

operating tool, which becomes broken, or

nonusable from any cause; and to repair a barrel, or a hammer, or tool, it is only necessary to detach the supplemental or front section ofthe frame from the rear or main section and force the barrel needing repair from the head or casing, leaving the barrel so that the toolvcan be Withdrawn, or the` hammer withdrawn, or the barrel replaced by a new barrel, or any repair necessary can be made. It is to be understood `that the whole frame rality of drills, each having bits or cutters, the construction and arran ement can be used with other .tools than t e s ecial head substanti with bits or cutters shown and escribed.

. What I claim as new and desire to secure by Letters Patentisz.

1. In a pneumatic drill, a frame having formed therein a plurality of fluid induction V assages in communication with a circumerentlal passage, and a pluralityiof iluid eduction passages in 'communication with a circumferential assage, to and discharging fluid from a plurality of pneumatic hammers carried bythe frame, substantially as described.' f

2. In a pneumatic drill, a frame having formed therein a plurality of fluid inductionv passages 1n communication with a circumferentlal passage, a plurality of uid eduction passages 1n communication with a circumferential passa e, for supplyin fluid to and discharging lulidfrom aIplur tyofr neumatic hammers carried by t e franc, an -a plurality oflongitudinal passages on the'exterior Y lyingvllilura tyof pneumatic hammers carried by of the frame, substantial] as described.

3. In a pneumatic dri a frame -having formed therein a plurality of uid induction passages in communication with a circumferentialpassage, a plurality of fluid eduction assagesin communication -with a circumerentlal'passage, for suppl 'y fluid to and discharging fluid matic hammers carried by the frame, and a plurality of longitudinal passages on theinterior of the frame for the esca of the dust and fine articles from witllln the frame,

ally as described.

I4,.-.In a pneumatic drill, a frame having formed therein a plurality of fluid induction in communication with .a circumerential tion passages 1n communication for vsupplying fluid from a p urality of pneu` passage, a plurality or' iluid educcumferential passage, for supplying fluid to and discharging' luid from a plurality of pneumatic hammers carried by the frame,

exterior -of the frame for the Awithdrawal of front of the tool, and a pluralityfof llongitudinal passages on the intel'ior of the frame for theescape of the dust and line particles from within the frame, substantially as described. f 5. Inlav neumatic drill, thecombination of a frame having formed therein a plurality of lluid induction assages in communication with a circumilerentlal passage, a plurality of fluid eduction `passages in communication with a circumferential passage for suplplying Huid to and discharging Huid-from "a urality of barrels, and a plurality of barre in communication with said passages and entered into the front end yof the frame, each barrel adapted to receive and retain a driving hammerand a driven stem in otperating the'drill, substantially as describe y 6. In a neumatic drill, the combination of a frame Iliaving formed therein a plurality 4'of iluid induction assages in communica- `tion with a circumibrentlal passage, a plucation with a circumferential passage for supplying fluid to and discharging lluid fromra plurality ofbarrels, a plurality ofbarrels 1n communication with said assages and entered into the front end oi) the frame, each barrel adapted to receive and retain a hamand cutting tools, and the llui'd eduction passages, of the frame dischar 'ng in front of the tool heads in o erating t e drill, substantially as ,describedA y 7. In a pneumatic drill, the combination of a circular frame having formed therein a plurality of induction passages in communication with a circumferentia passage, a plucation with acircumferential l passage for supfluid to and discharging liuid from a thecircular frame, a plurality of barrels en- .tered into the front of the frame, each barrel having a central'circular chamber provided with-a fluid induction section in communication with the induction assages of the frame for admitting yfluid to t e chamber in operating a dri hammer, and each central circular Achamber provided with a fluid eduction section in communication with the eduction assage of the frame for discharging fluid m the chamber of th`e barrel at the frontend of the frame, and each circular chamber adapted to receive and retain a'driving hammer 1n o erating the drill, substantially as described? Ina pneumatic drill, the combination of a cimular'fame havingformed therein a a plurality of longitudinal passages on the rality of fluid eduction passages in commumthe cuttings, dust and iine particles from in f Vrality of fluid eduction passages in communimer, and'adriven stem, carrying a' tool head plurality of fluid iiiduct-ion passages in coniimiiiicatioii with a circumferential passage, a plurality of fluid eduction passages in communication with a circumferential passage,

for supplying fluid to and discharging fluid from a plurality of pneumatic hammers carried by the frame, a plurality of barrels in communication with said passages. each bariel adapted to ieceive a driving hammer and a driven stein and carried by the front section ot' the frame, each barrel having a central ciicular chamber provided with a fluid induction section in communication with the induction passages of the frame for admitting fluid to o erate the hammer. and each barrel having flie chamber provided with an eductioii se tion in communication with the ediictioii pv ssages of the frame, for discharging fluid from the chamber Aof the barrel at the. front cud of the frame, a driving hammer operative in the chamber of each barrel,

anda driven stem operative in the cliainher of each barrel forward of the hammer and carrying an opera-ting tool, substantially as described.

9. In a pneumatic drill, the combination of a circular frame having formed therein a plurality of fluid induction passages in communication with a circumferential passage, a plurality of fluid eductioii passages iii communication with a circumferential passage, for supplying fluid to and discharging fluid from a plurality of pneumatic hammers carried by the frame, a pluiality of barrels in communication with said passages, each bariel adapted to receive a driving hammer and i a driven stem and carried b v the front section of the frame, each barrel having a central circular chamber provided with a fluid eduction section for discharging fluid, and a fluid induction chamber for fluid to act-,and

l recede and drive forward the hammer, and

each barrel having a radial port in communication with a fluid induction passage of the frame and aradial port in comiiiuiiicatioi with the fluid eduction passage of the fra me and each barrel having a fluid induction pas sage in communication with the fluid indue.A tion section of the chamber of the barrel` and a fluid induction passage in communication with the fluid educ-tion section of the chamber of the barrel, substantially as described.`

10. In a pneumatic drill. the combination of a frame having foi'iiied therein a plurality of fluid induction passa-ges in communication with a circumferential passage, a plurality of eduction passages in communication with a circumferentialpassage, for supplying fluid 60 to and discharging fluid from a plurality of pneumatic hammers carried by the frame, and a plurality of pneumatic liaiiiiiiei's arl l l t ranged iii circular relation around the frame in communication with said passages and a u G n operated by fluid inducted through the fluid induction passages of the frame, substantially as described.

l1. In a pneumatic drill. the combination of a frame having formed therein a plurality of fluid induction passages in communication with a circumferential passage, a plurality of eduction passages in communication with a circun'ifcrential passa-ge` for supplying fluid to and discharging fluid from a plurality of pneumatic hammers carried by the frame, a plurality of pneumatic hammers arranged in circular relation around the frame in communication with said passages fand operated by fluid inducted through the tfluid induction passages of the frame, and a central pneumatic hammer operated b v fluid supplied from the fluid induction passage of the frame, substantially as described.

l2. In a pneumatic drill. the combination of ar circular frame having formed therein a plurality of fluid induction passages in communication with a circumferential passage, a plurality of fluid educ-tion passages in coinimiiiicatioii with a circumferential passage, for supplying fluid to and discharging fluid fi'oiii a plurality of pneumatic hammers carriedby the frame, a plurality of barrels for pneumatic hanmiers carried by the front section of the frame, and arranged iii circular relation and in communication with said passages, a plurality of driving hammers one for cach barrel, a plurality of driven stems one for each barrel, an operating tool for each stem, and a fluid supply tube connected with thtframe and supplying fluid to all the passages of the frame, substantiallyias described.

13. In a pneumatic drill, the combination of a fiaiiie having formed therein a plurality of fluid induction passages in communication with a circumferential passage, a plurality of fluid eductioii passages in communication with a circumferential passage, for supplying fluid to and discharging fluid from a plurality of pneumatic hammers carried by the frame, av plurality of barrels for pneumatic hammers carried by the front section of the frame in communication with said passages and arranged in circular relation, a plurality of driving hainn'ters one for each-barrel, a plurality of driven .stems one for each barrel, each stem carrying an operating tool, and a fluid supply tube connected with the frame and having circuinferentially around its cxterior a flight or convcyer, substantially as described.

14. In a pneuniat.l drill` the combination of affraiiie having formed theici a plm ali ty of fluid induction pasages in communication with a circumferential passage, a plurality of fluid eduction passages in communication with a-circumferential passage, for su plying fluid to and discharging fluid from a p urality of neumatic hammers carried by the frame, a. p urality ofbarrels for pneumatic hammers carried by the front section of the frame in communication with said passages and arranged in circular relation, a plurality of drivi substantially as described.

ing hammers one for each barrel, a plurality of driven stems one for each barrel, an o erating tool for each stem, a central bar re for a plneumatic hammer, a driving hammer Wit in the central barrel, a driven stem Within the central barrel, an operating tool for the driven stem, and a fluid sup ly tube connected with the frame and sup lying fluid to the plurality of barrels and t e central barrel,

15. In a pneumatic drill, the combination of a fluid supply tube, a closing head for a frame and having a central chamber in communication with the fluid supply tube, with radial passages leading from the central chamber and each terminating in a port, a

`frame having a plurality of longitudinal pas- 20 munication with the fluid supply tube, with radialY passages leading from the central chamber and each terminating in a port, a frame having a 'plurality of, longitudinal passages, one passage for eachi radial sage and port of the closing head, a plurality of barrels carried by `the frame in communication with said passages and arranged in circular relation, a driving hammer for each barrel, and a driven stem for each barrel, each stem carrying a tool head and tool and passages in t-he frame, and barrels for inducting and educting fluid in operating the driving hammers, a central supply tube Within the frame and connected with the central chamber of the closing head, a barrel carried by the central supply tube, a driving hammer in the barrel, a driven stem in the barrel and carrying Ia tool head and tool, and passages in the barrel of the central tube for inducting and educting fluid and operating the driving hammer, substantially as described.

17. In a pneumatic drill, the combination of a frame consisting of a closing head having a central chamber and radial passages for 3. inducting fluid, a main section having longipassages for inducting fluid, a front 'tudinal section aving longitudinal and cross passages 'for inducting and educting fluid, a plurality of barrels for pneumatic vhammers arranged in a circle in the front section of the frame and in communication with said passages, `a driving hammer for each barrel,

and a driven stem for each barrel, each stem carrying a head`With operating tools, substantially as described;

18. In a pneumatic drill, the combination of a frame consisting of a closing head having a central chamber and radial passages4 for inducting fluid, a main section having longi` tu'dinal assag'es for inducting fluid, a front section aving longitudinal and cross passages for inducting and educting fluid, a plurality of.barrels for pneumatic hammers arranged in a circle in the front section of the frame and in communication with said assagve, a driving hammer for each barre a dri n stem for each barrel, each stem carrying a head with operating tools, a central tube for inducting fluid from the central chamber of the closing head, a barrel carried by the central tube and having induction and eduction passages for fluid, a hammer in the barrel, and a driven stem in the barrel and carrying a head with operating tools, substantially as described.

MARTIN HARDSOCG. Witnesses:

FRED B. HARnsocG, W. A. Wenn. 

